A tetrahydropyran derivative represented by the following formula (8) is a compound that is important as a starting material such as for medicines (Patent Document 1). As an existing preparation method, there are known a method of preparing from 5-alkoxy-4-penten-1-ol (Patent Document 1) and a method of synthesizing from 5-hexen-1-ol (Non-patent Document 1).

However, the preparation method of Patent Document 1 has not been accepted as a practical method because of the use of highly toxic osmium.
On the other hand, when an attempt has been made wherein the above compound is synthesized while applying the method set out in the Non-patent Document 1 as it is, it has been found that the reaction yield and steric selectivity are so low that this method is not suited for quantity synthesis.